The invention relates to insulative support material for a catalytic converter, and in particular, to the end-cone portion wrapped therewith.
Catalytic converters are employed in vehicles to catalyze exhaust gasses. Typically, a catalytic converter is a cylindrically shaped canister containing a subassembly of a catalyst portion surrounded by insulative support material. This subassembly is then covered by an outer-layer.
As the exhaust system receives hot gasses that are potentially harmful to other vehicle components, catalytic converters are usually well insulated. Therefore, an intumescent insulation layer, also known as a support material layer or support mat, is positioned about the catalyst portion of a typical catalytic converter. Inner end-cones are affixed at the inlet and outlet portions of the catalyst portions. These inner end-cones serve as both caps and ends to catalytic converter housings and provide openings for exhaust gasses to flow into and out of the catalytic converter. The insulative support material, however, should also cover the end-cone portions. Therefore, the support material layer is generally provided to surround and support the end-cone portion of the catalytic converter.
One method of manufacturing catalytic converters is to provide a pre-made canister and stuff it with the catalyst substrate and the insulation pad. In this method the catalyst substrate is wrapped with an insulation layer of a selected thickness and weight (various weights are employed for various applications and desired properties). The assembly is then forced through a reduction cone and into the converter shell where pressure can be required to accomplish the insertion of the assembly into the can. The method is costly and can result in support material that is overly compressed.
A commonly preferred method for producing a catalytic converter is known as xe2x80x9cthe tourniquet methodxe2x80x9d. The tourniquet method dispenses with the reducing cone and thus avoids the high insertion pressures on the catalyst substrate and support material. The method places the substrate and support material assembly into a canister open on one longitudinal edge. The canister is closed around the assembly by straps and compressed to the desired size. The open ends of the canister will, in this position, be overlapping and then are welded together. This method is also expensive and labor intensive. Further, due to this overlap, engineering design consideration must be given to the space alteration inside the canister Furthermore, the overlapped edge causes a density change in the support material in the area of the overlap. This also can be expensive and can result in support material that is overly compressed.
What is needed in the art is a low cost catalytic converter assembly that is durable and easily assembled.
The deficiencies of the above-discussed prior art are overcome or alleviated by the present invention of a relieved support material for a catalytic converter. The relieved support material for a catalytic converter comprises a support material having a density and one or more relief cuts wherein said one or more relief cuts allow said support material to engage an inner end-cone without increasing the density.
The catalytic converter with the relieved support material of the present invention comprises: a catalyst substrate comprising a catalyst, said catalyst substrate having a first end and a second end and a perifery; an inner end-cone having a pinch trim end, wherein said pinch trim end of said inner end-cone is connected to said first end of said catalyst substrate, wherein said inner end-cone forms an inlet or outlet of said catalyst substrate; support material having relief cut, wherein said support material is concentrically disposed about the periphery of said catalyst substrate and around said inner end-cone such that said pinch trim end is disposed within said relief cut; and an outer-layer shell concentrically disposed about an external surface of said support material.
The method of producing a catalytic converter with a relieved support material of the present invention comprises: supplying a catalyst substrate having a periphery, a first end and a second end and comprising a catalyst; connecting a first pinch trim end of a first inner end-cone to said catalyst substrate first end and a second pinch trim end of a second inner end-cone to said catalyst substrate second end to form a catalyst assembly; making a first relief cut across a support material near a first end of said support material to be disposed at said first end of said catalyst substrate; wrapping said support material concentrically around said catalyst assembly to form a support assembly, wherein said first pinch trim end of said first inner end-cone is disposed within said first relief cut; disposing said support assembly concentrically within an outer-layer shell.